Obesity has been strongly associated with systemic inflammation and, to a lesser degree, with oxidative stress, although the causal relationships among these factors are unclear. Our recent study demonstrated an expression of the components of the melanogenic pathway and the presence of melanin in visceral adipose has raised questions regarding the possible role of melanogenesis in adipose tissue. We also found larger amounts of melanin in the adipose tissue of obese patients relative to lean ones. We hypothesize that melanin, a pigment known for its antioxidant and anti-inflammatory properties, may scavenge reactive oxygen species and abate oxidative stress and inflammation in adipose tissue. It is possible that the α-melanocyte-stimulating hormone or its synthetic analogues could be used to stimulate melanin production in adipocytes and, by that, to prevent the development of the secondary complications of obesity, namely, Non-Alcoholic Fatty Liver Disease, Metabolic Syndrome, Cardiovascular conditions and PCOS.

This research has been supported by a grant from the Thomas F. Jeffress and Kate Miller Jeffress Memorial Trust and by the Intramural Research Program of the National Cancer Institute at NIH.

Figure 1. Fontana-Masson stain of human adipose tissue demonstrates melanin pigment (black staining) mainly in the periphery of the adipocytes.
A and B. Multiple conglomerates of melanin granules are present at the periphery of the adipocytes in adipose tissue from morbidly obese subjects (20x magnification).
C and D. Melanin granules are scarce in the adipocytes of adipose tissue from non-obese subjects (20x magnification).
E. No melanin granules were observed in the microvessels located in the adipose tissue (20x magnification).
D. Melanin staining in skin tissue used as a positive control (10x magnification).